This mostly applies in extreme cases but it is a good rule of thumb to me, and here is why.
Once upon a time, I had a 300+ lbs double bottom fiberglass boat to fly with a Beaver. We needed to be four guys to tie the boat the evening before the flight.
The boat looked so big once tied that we were wondering if the plane was carryig it or it was carrying the plane. Doing it in turbulence was definitely ruled out. Of course, we tied the boat on the left side with straps and ropes.
When I flew it the next morning in still air, along with its owner, I needed lot of aileron to keep the aircraft level, as well as climb flaps, or we plummeted. Attempting a left turn would have been suicide. The trip was only 50 miles but seemed to last a life.
Guess what my brilliant passenger, who supposedly knew exactly where we were going did? He found out on final that we were in the wrong pass of the Y shaped lake!!!
Never anymore! I thought.
I think the rules have changed since and there are certainly some limitations regarding external loads/aircraft type by now.
RB






